38 weeks pregnant blood on toilet paper

Bleeding can happen at any time during pregnancy. Placenta previa can cause bleeding late in pregnancy. This means after about 20 weeks.

When the placenta is attached close to the opening of the uterus (cervix) or covers the cervix, it is called placenta previa. There are 3 types of placenta previa:

  • Total placenta previa. The placenta completely covers the cervix.
  • Partial placenta previa. The placenta is partly over the cervix.
  • Marginal placenta previa. The placenta is near the edge of the cervix.

What causes placenta previa?

Researchers don't know what causes placenta previa. It is more likely to happen with certain conditions. These include:

  • Past pregnancy
  • Tumors (fibroids) in the uterus. These are not cancer.
  • Past uterine surgeries or cesarean deliveries
  • Woman who is older than 35
  • Woman who is African American or of another nonwhite ethnic background
  • Cigarette smoking
  • Placenta previa in a past pregnancy
  • Being pregnant with a boy

What are the symptoms of placenta previa?

The most common symptom of placenta previa is bright red, painless bleeding from the vagina. This is most common in the third trimester of pregnancy.

The symptoms of placenta previa may look like other health conditions. Make sure to see your healthcare provider for a diagnosis.

How is placenta previa diagnosed?

Your healthcare provider will ask about your health history. He or she will do a physical exam. The provider will also do an ultrasound. An ultrasound uses sound waves to make a picture of the organs. It can show where the placenta is and how much is covering the cervix. You may have a transvaginal ultrasound instead.

An ultrasound may show that a placenta is near the cervix in early pregnancy. But, only a few women will develop true placenta previa. It is common for the placenta to move away from the cervix as the uterus grows.

How is placenta previa treated?

There is no treatment to change the position of the placenta. You may need:

  • More ultrasounds to track where the placenta is
  • Bed rest or hospital stay 
  • Early delivery of the baby. This will be based on how much bleeding you have, how far along your baby is, and how healthy the baby is.
  • Cesarean delivery
  • Blood transfusion for severe blood loss

What are the complications of placenta previa?

The greatest risk of placenta previa is too much bleeding (hemorrhage). Bleeding often happens as the lower part of the uterus thins during the third trimester of pregnancy. This causes the area of the placenta over the cervix to bleed. The risk of bleeding is higher if a lot of the placenta covers the cervix. Other complications include:

  • Placenta doesn't attach to the uterus as it should
  • Slowed growth of your baby in the womb
  • Preterm birth. This means before 37 weeks of pregnancy.
  • Birth defects

When should I call my healthcare provider?

Call your healthcare provider about any bleeding you have while pregnant. Bleeding during pregnancy may not be serious. If the bleeding is moderate to severe, or you have pain, contact your healthcare provider right away.

One out of 10 women will have vaginal bleeding during their 3rd trimester. At times, it may be a sign of a more serious problem. In the last few months of pregnancy, you should always report bleeding to your health care provider right away.

You should understand the difference between spotting and bleeding:

  • Spotting is when you notice a few drops of blood every now and then on your underwear. It is not enough to cover a panty liner.
  • Bleeding is a heavier flow of blood. With bleeding, you will need a liner or pad to keep the blood from soaking your clothes.

What Causes Bleeding Later in Pregnancy?

When labor begins, the cervix starts to open up more, or dilate. You may notice a small amount of blood mixed in with normal vaginal discharge, or mucus.

Mid- or late-term bleeding may also be caused by:

  • Having sex (most often just spotting)
  • An internal exam by your provider (most often just spotting)
  • Diseases or infections of the vagina or cervix
  • Uterine fibroids or cervical growths or polyps

More serious causes of late-term bleeding may include:

  • Placenta previa is a problem of pregnancy in which the placenta grows in the lowest part of the womb (uterus) and covers all or part of the opening to the cervix.
  • Placenta abruptio (abruption) occurs when the placenta separates from the inner wall of the uterus before the baby is born.

What to Tell Your Health Care Provider

To find the cause of your vaginal bleeding, your provider may need to know:

  • If you have cramping, pain, or contractions
  • If you have had any other bleeding during this pregnancy
  • When the bleeding began and whether it comes and goes or is constant
  • How much bleeding is present, and whether it is spotting or a heavier flow
  • The color of the blood (dark or bright red)
  • If there is an odor to the blood
  • If you have fainted, felt dizzy or nauseated, vomited, or had diarrhea or a fever
  • If you have had recent injuries or falls
  • When you last had sex and if you bled afterward

What Should Happen Next?

A small amount of spotting without any other symptoms that occurs after having sex or an exam by your provider can be watched at home. To do this:

  • Put on a clean pad and recheck it every 30 to 60 minutes for a few hours.
  • If spotting or bleeding continues, call your provider.
  • If the bleeding is heavy, your belly feels stiff and painful, or you are having strong and frequent contractions, you may need to call 911 or your local emergency number.

For any other bleeding, call your provider right away.

  • You will be told whether to go to the emergency room or to the labor and delivery area in your hospital.
  • Your provider will also tell you whether you can drive yourself or you should call an ambulance.

References

Baeseman ZJ. Vaginal bleeding in pregnancy. In: Kellerman RD, Rakel DP, eds. Conn's Current Therapy 2021. Philadelphia, PA: Elsevier 2021:1227-1229.

Francois KE, Foley MR. Antepartum and postpartum hemorrhage. In: Landon MB, Galan HL, Jauniaux ERM, et al, eds. Gabbe's Obstetrics: Normal and Problem Pregnancies. 8th ed. Philadelphia, PA: Elsevier; 2021:chap 18.

Hull AD, Resnik R, Silver RM. Placenta previa and accreta, vasa previa, subchorionic hemorrhage, and abruptio placentae. In: Resnik R, Lockwood CJ, Moore TR, Greene MF, Copel JA, Silver RM, eds. Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 8th ed. Philadelphia, PA: Elsevier; 2019:chap 46.

Salhi BA, Nagrani S. Acute complications of pregnancy. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 178.

Review Date 10/5/2020

Updated by: John D. Jacobson, MD, Professor of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda Center for Fertility, Loma Linda, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

Does light bleeding mean labor is near?

You might notice an increase in vaginal discharge that's clear, pink or slightly bloody. This might happen several days before labor begins or at the start of labor. However, if you have vaginal bleeding that is as heavy as a typical menstrual period, contact your health care provider immediately.

How long after the bloody show will I go into labor?

How long after experiencing bloody show will you go into labor? If you've experienced bloody show, you can usually expect to go into labor within the next day or two — unless you're a fast starter, in which case you could have your first contraction within the next several hours.

What does it mean when you bleed at 38 weeks pregnant?

The bloody show refers to vaginal discharge that occurs at the end of your pregnancy. It's a sign that your mucus plug has loosened or already has been dislodged. During pregnancy, the cervix is covered by a thick plug of mucus that helps protect the baby. The mucus literally “plugs” your uterus.

Should I be worried if I see blood when I wipe while pregnant?

Bleeding and spotting from the vagina during pregnancy are common. Up to 1 out of 4 (up to 25%) of all pregnant women have some bleeding or spotting during their pregnancy. Bleeding and spotting in pregnancy don't always mean there's a problem, but they can be a sign of miscarriage or other serious complications.